[GRASS-dev] GRASS GIS raster files: LZW compression?

Markus Metz markus.metz.giswork at gmail.com
Thu Oct 26 00:25:08 PDT 2017


On Wed, Oct 25, 2017 at 10:40 PM, Markus Neteler <neteler at osgeo.org> wrote:
>
> Hi devs,
>
> while playing with the SRTM 30m world I see that there is a difference
> of 66GB in size between LZ4 (larger) and DEFLATE (smaller). While this
> is not a surprise I was wondering if LZW compression could be brought
> back. AFAIK the license issue is gone for a while and indeed GRASS got
> a special permit back in 1988 according to the old source code.
>
> Would that make sense?

You could test with compress (LZW) and gzip (DEFLATE based on LZ77) if that
would make sense.

Implementation would be a bit of an effort: either adapt from the source
code of compress or from GDAL's LZW compression for Tiff.

Markus M
>
> Markus
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